Very interesting infographic on how much land space would be required to keep your family of four self-sufficient. According to their bottom-line calculation, it would take about 1.5 acres, assuming you bought your own wheat, although almost 2 acres if you grew your own wheat.
I am left wondering, though, if they only calculated for one growing season. In the desert you can grow stuff literally year round, 12 months out of the year. Which means you can bring in at least 4 harvests a year of your typical veggie crops, and at least 3 harvests a year of your grain crops. Presumably that would lower the amount of land space you would need.
When you start talking about self-sufficiency on your own acre, it is important to think in terms of Permaculture principles. Chickens, goats, pigs, and fish are necessary for a functioning circular ecosystem, consuming waste while contributing fertilizers for the soil.
You would also need to re-route almost all your wastewater into grey water systems. A typical 20 minute show provides enough irrigation water to keep your garden soil moist even in the summer time.
Creating grey-water systems here in Arizona is difficult because most houses are built on concrete slabs. Finding or building a post-and-beam foundation house, or easiest of all, using a manufactured home, are the best alternatives.
The good news, if you follow these tips, you can have a functioning SELF-SUFFICIENT homestead in the desert ON ONLY AN ACRE. Quite amazing, if you ask me.
Here is their webpage with the infographic: http://1bog.org/blog/live-off-the-land-2/